This invention relates to a method and apparatus for cleaning the surface of a body of liquid. It relates particularly to a floating skimmer and incorporates an articulated weir which rides on a float so as to provide a self compensating cascade action for skimming the surface of liquid surrounding the skimmer.
The majority of the dirt and debris that gets into a body of liquid is airborne. Liquids have a surface tension which tends to retain most of this airborne dirt and debris in a relatively tough film on the very upper surface. The removal of this contaminated film, or meniscus, provides an efficient and thorough method of cleaning polluted bodies of liquid. However, to be truly effective, the meniscus or film removing skimmer should be versatile enough to act under many different conditions. It should also be constructed to remove the meniscus and not any substantial quantities or layers of liquid underneath this tough upper film. Depending upon the particular installation, the skimmer should therefore be self-compensating for differences in viscosity and rate of effluent leaving the skimmer.
In addition to being self-compensating, there are many applications in which the skimmer should also be manually adjustable in the course of operation. This permits an operator to "tune" the device to maximize its effectiveness as a skimmer.
Some floating skimmers described in the prior art have proposed a floating annular weir which could create the desired skimming effect under ideal conditions. However, under conditions of agitation, such as when being rocked by waves, the lower edge of such prior art devices would tend to dig too deeply into the liquid. This results in loss of the meniscus-pulling effect. Also the upper edge of such prior art devices would tend to pull out of the water under such conditions, and this would result in loss of all the pulling effect.